1. Field of Invention
This invention pertains to an all plastic drum of the kind having an open top and a cover, and more particularly to a plastic drum designed for safely transporting various powdery materials and the like.
2. Description of the Prior Art
Open top plastic drums provided with round plastic covers are very desirable as a means of transporting various types of solid materials, which may be granular, in the form of powders, as well as semi-liquids or pastes. Depending on the nature of the material to be transported, these drums are subject to different governmental regulations. Drums for regulated materials, i.e. materials dangerous or hazardous to public health, are regulated by the United States Department of Transportation (DOT) as well as by the United Nations. The DOT requires that a drum for transporting a regulated material must be able to withstand the so-called drop test. This test consists of loading a drum with 400 pounds of sand, orienting the drum so that a vertical line passes through a top edge, the center of the drum, and a bottom edge, and then dropping the drum straight down, along the line, for a distance of 4 feet, onto a cement floor, so the impact is absorbed by the bottom edge. If the drum spills any of its contents, it has failed the test. This test simulates a worst-case condition for accidentally dropping a drum from a truck bed or a fork lift.
Drums for transporting non-regulated materials, such as adhesives, pastes, waxes, etc. are subject to other regulations promulgated by various and international organizations, including the United Nations. One such test, the tip-over test, consists of filling a drum with a heavy material, such as water, closing it and then tipping it over on a concrete floor on its side. Again, if the drum spills its contents, it fails the test.
As far as we know, the plastic drums presently available are not capable of passing both of these tests. The present drums fail to pass the tests because the impact generated during the tests forces the sidewalls of the drum to distort from a nominally cylindrical configuration to an oval or elliptical configuration. The round cover mounted on the drum is not able to conform to this drastic change and parts of the cover separate from the drum at least temporarily allowing the drum contents to spill.